The present invention relates to a cylinder and, more particularly, to a cylinder which can be easily adjusted to suit field conditions.
Cylinders have numerous applications and are often used in machines to move parts or provide lifting mechanisms. Typically, cylinders comprise a hollow outer cylindrical casing, which includes a closed end on one end of the casing and a removable end cap on an opposed end of the casing. A piston, which is mounted on a rod, is positioned in the cylindrical casing and includes a seal, which seals the space between the piston and the cylindrical casing. The free end of the rod extends through the removable end cap for connection to the machine. In a double acting cylinder, the piston divides the hollow interior of the cylindrical casing into two reservoir areas. Conventionally, in a double acting cylinder, the casing includes two ports--a first port which is in communication with the first reservoir, and a second port which is in communication with the second reservoir. In this manner, fluid, such as hydraulic fluid, air, or air over oil, can be delivered to the respective reservoirs to apply pressure to the piston to move the piston and rod along the longitudinal axis of the hollow cylindrical casing. Thus, the free end of the piston, which extends through the end cap of the hollow cylindrical casing, extends or contracts in response to the pressures of the fluid in the reservoirs.
Typically, both ports are provided on the hollow-casing wall. As a result, the relative positions of the two ports are fixed, which in some instances limits the application of the cylinders. Furthermore, by locating the ports in the casing, the overall length of the casing, and therefore the cylinder, is proportionately increased by the diameters of the ports. Again, as a result, in some applications the use of cylinders is precluded.
Proposals have been made to include a port in the base of a cylinder. For example, U.S. Pat. No. 2,890,917 to Prince and U.S. Pat. No. 3,494,652 to Langland each disclose double acting hydraulic cylinders with ends (32 and 26, respectively) which are held in place by snap rings and/or a retaining ring. In the Langland cylinder, the snap rings limit the movement in both left hand and right-hand directions. As a result, the positions of the ports 30 and 39 are fixed relative to each other, and removal of the snap rings is needed to permit adjustment.
Typically, cylinders further include a coupler or attachment at each end of the cylinder, which allows the pressure plate or rod of the cylinder to be connected to a respective piece of equipment or machinery. However, these attachments are typically fixed with respect to the body of the cylinder, such that the attachment cannot be rotated to align with the corresponding attachment of the respective equipment. Consequently, where an application requires a different orientation of the attachment on the cylinder, the application will require a custom cylinder having attachments oriented specifically for that application.
Consequently, there is a need for a cylinder with adjustable ports and adjustable attachments to facilitate and simplify installation. Furthermore, there is a need for a cylinder which has a reduced length to increase its application. With reduced lengths, the overall weight and cost of equipment and machines employing such cylinders may be significantly reduced.